Switching device for a camera

ABSTRACT

A release switch is directly activated by a self-timer button, and a shutter release button first activates a photometric switch, then the release switch. The self-timer operation is carried out in response to the activation of only the release switch, a photometric operation is carried out in response to the activation of only the photometric switch, and a shutter release operation is carried out in response to the sequential activation of both the photometric switch and the release switch.

BACKGROUND OF THE INVENTION

The present invention relates to a switching device to be used in acamera and, more particularly, a switching device for controlling bothself-timer and normal operations. Conventionally, when a self-timeroperation in a camera is to be executed by a camera, the operationalmode is first changed to a self-timer standby mode by means of aself-timer switch. Thereafter, the shutter release button is depressed,and the self-timer operation is carried out.

However, the use of many independent switches and modes increases thecost of the camera and makes the operation of the camera complicated.Furthermore, in conventional cameras, switching devices (such as, forexample, shutter release and self-timer buttons) consist of manyswitching parts, springs and lead wires.

The combination of these factors results in many problems, among them ahigh part count, an overcomplicated structure, poor assemblingefficiency, and high cost.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide animproved switching device for a camera, capable of readily executingself-timer photographing, yet making the structure simple whileimproving assembling efficiency.

In order to meet the objects of the invention, a switching device for acamera includes a photometric switch; a release switch; a shutterrelease button, operatively connected to the release switch and to thephotometric switch, for turning On the photometric switch when halfdepressed and turning ON both the release switch and the photometricswitch when further depressed; and a self-timer button, operativelyconnected to the release switch, for turning ON only the release switchwhen depressed. Accordingly, the switching device of the camera is ableto discriminate the desired operation of self-timer or normaloperations.

Preferably, the switching device further includes control means fordetecting the turning ON of the release switch and the photometricswitch and for executing a self-timer operation when the release switchis ON but the photometric switch is OFF. In this manner, the switchingdevice sets and executes the self-timer operation in response to acombination of switch states when the self-timer button is depressed.

In this case, the control means preferably executes a photometricoperation when the release switch is OFF but the photometric switch isON, and executes a shutter release operation when the release switch isON and the photometric switch is ON. In this manner, the switchingdevice sets and executes subsequent photometric and shutter releaseoperations in response to a combination of switch states when theshutter release button is depressed.

In one particular case, the switching device includes a shutter releasecontact arranged to be depressable by the shutter release button; aself-timer contact arranged to be depressable by the self-timer button;a photometric contact opposing the shutter release contact, provided tothe photometric switch; and a first and a second electrical contactprovided to the release switch, the first electrical contact opposingthe self-timer contact, and the second electrical contact opposing thephotometric contact. Accordingly, the appropriate switches can beactivated by the closing of contacts in the correct combinations whenthe buttons are depressed.

In this case, when the shutter release button is half depressed, theshutter release contact electrically connects to the photometriccontact, and when the shutter release button is further depressed, allof the shutter release contact, the photometric contact, and the secondelectrical contact of the release switch electrically connect. When theself-timer button is depressed, the self-timer contact electricallyconnects to the first electrical contact of the release switch. Thecorrect combinations of contact positions to electrically connect theswitches are achieved with this arrangement of contacts.

In this arrangement of contacts, the switching device preferablyincludes control means for executing a self-timer operation when theself-timer contact is electrically connected to the release switch, forexecuting a photometric operation when the shutter release contact iselectrically connected to the photometric switch, and for executing ashutter release operation when all of the shutter release contact, thephotometric contact, and the release switch electrically connect.

According to a particular development, the photometric switch includes aphotometric switch plate upon which the photometric contact is provided,and the release switch includes a release switch plate upon which thefirst and second electrical contacts are provided. The use of switchplates facilitates the arrangement of the contacts. In this case, thephotometric switch plate and the release switch plate are formed fromconductive and resilient plate spring material, and the photometricswitch plate is formed substantially in a U-shape, surrounding therelease switch plate. The combinations of contact positions can therebybe compactly achieved. A particularly favorable arrangement isimplemented when the U-shape of the photometric switch plate includes anupper arm above the release switch plate and a lower arm below therelease switch plate, and the photometric contact is formed on the upperarm.

In another development, the self-timer contact and the shutter releasecontact are provided on a unitary common switch plate, and thephotometric switch plate and the release switch plate are supported by achassis of the camera, and the common switch plate, shutter releasebutton, and self-timer button are supported by a front decorative platefixed to the camera body. In this case, each of the contact-supportingswitch plates are arranged in a compact space and can be easilyassembled.

In a preferred arrangement, the common switch plate is provided with afirst resilient arm bearing the shutter release contact and a secondresilient arm bearing the self-timer contact, and the first resilientarm and the second resilient arm bias the shutter release button and theself-timer button, respectively, toward undepressed positions. In thismanner, the elements of the common swatch plate serve as electricalcontacts and as resilient members to provide, a return action in thebutton operation.

According to one preferred embodiment, a plurality of resilient tabs,for holding the release switch plate and the photometric switch plate,are provided on-the chassis displaced from one another. The resilienttabs have clearances therebetween into which the release switch plateand photometric switch plate are inserted. In this manner, the assemblyof the switch plates is easily accomplished.

In this case, the plurality of resilient tabs preferably includes meansfor locking the release switch plate and the photometric switch plateinto the clearances therebetween. The release switch plate may beinserted and locked between a first and a second resilient tab of theplurality of resilient tabs, and the photometric switch plate may beinserted and locked between the second resilient tab and a thirdresilient tab of the plurality of resilient tabs. In this manner each ofthe switch plates is snapped into place, and resilient tabs canparticipate in holding more than one switch plate, a minimum number ofresilient tabs is used to hold the switch plates.

In another preferred embodiment, the self-timer contact and the shutterrelease contact are provided on a unitary common switch plate, and thecamera chassis is provided with an electrically conductive plate forconnecting the common switch plate with common DX code conductivepattern terminals of a film cartridge inserted in the camera. In thiscase, the camera may detect whether or not a film having a DX codeconductive pattern portion defining a predetermined group of film speedsis inserted in the camera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view showing a mounting arrangement of anembodiment of the switching devise according to the invention;

FIG. 2 is an partially exploded view showing an arrangement of switchesin the embodiment of a switching device;

FIG. 3 is a perspective view showing the assembled condition of theembodiment of a switching device;

FIG. 4 is a front view showing the mounting of the switching device to acamera body, from the viewpoint of arrow Y in FIG. 3;

FIG. 5A is a sectioned view along line X--X of FIG. 3, showing a halfdepressed shutter release button;

FIG. 5B is a sectioned view along line X--X of FIG. 3, showing a fullydepressed shutter release button;

FIG. 6 is a sectioned view along line X--X of FIG. 3, showing adepressed self timer button;

FIG. 7 is a block diagram schematic of the embodiment of a switchingdevice;

FIG. 8 is a timing chart explaining the operation of a normal shutterrelease operation when the shutter release button is depressed; and

FIG. 9 is a timing chart explaining the operation of self-timeroperation when the self-timer button is depressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiment of a switching device according to the invention is shownin perspective and exploded views from FIG. 1 through FIG. 3. FIG. 1 isan exploded view showing the arrangement of switch plates on a plasticcamera body 13; FIG. 2 is a partially exploded view showing switchplates and buttons assembled to the plastic camera body 13; and FIG. 3is a perspective view showing the assembled switching device. In FIGS. 2and 3, the plastic camera body 13 is shown by a phantom line.

As shown in FIGS. 1 and 2, a photometric switch plate 21 and a releaseswitch plate 22 are supported by portions of the plastic camera body 13.The photometric switch plate 21 is formed from resilient and conductiveplate spring material, in a substantially a U-shape. A lower arm 21Dforms a lower side of the U-shape, while an upper (plate spring) arm 21Uforms an upper portion of the U-shape. An upper contact 21x, which actsas a photometric switch PH_(SW) in combination with a shutter releasecontact arm 19x (shown in FIGS. 2 and 4), is formed on the upper arm21U. The photometric switch plate 21 further includes a terminal 21bextending from the lower arm 21D, to which a signal connection to amicrocontroller 25 (shown in FIG. 7) is made.

The release switch plate 22 is formed from resilient and conductiveplate spring material, and is shaped having a mounting base 22a with along arm 22L and a short arm 22S extending in the same direction fromthe base 22a. The long arm 22L is bent up from the base 22a, and has afirst contact 22x near its distal end. The first contact 22x acts as arelease switch RLS_(SW) in combination with a self-timer contact arm 19y(shown in FIGS. 2 and 4). The short arm 22S is substantially coplanarwith the base 22a, and has a second contact 22y near its distal end. Thesecond contact 22y acts as the release switch RLS_(SW) in combinationwith the shutter release contact arm 19x (shown in FIGS. 2 and 4) andthe upper contact 21x. The release plate 22 further includes a terminal22b extending from the base 22a, to which a signal connection to thecontroller 25 (shown in FIG. 7) is made.

As shown in FIG. 1, a lower resilient locking tab 14, an upper resilientlocking tab 15, and a middle resilient locking tab 16 extend from thecamera body 3. The locking tabs 14, 15, and 16 are used for mounting thephotometric switch plate 21 and release switch plate 22. From theperspective of FIG. 1, the middle locking tab 16 is separated from theupper locking tab 15 in the vertical direction by a clearanceapproximately the thickness of the mounting base 22a of the releaseswitch plate 22, and is positioned to the left of the upper locking tab15. The lower locking tab 14 is separated from the middle locking tab 16in the vertical direction by a clearance approximately the thickness ofthe lower arm 21D of the photometric switch plate 21, and is positionedto the right of both the upper locking tab 15 and the middle locking tab16. The lower locking tab 14 is provided with an upwardly extendinglocking hook 14a. Similarly, the middle locking tab 16 is provided withan upwardly extending locking hook 16a.

One of the features of this embodiment is the supporting and mountingstructure for the photometric switch plate 21 and release switch plate22, including the locking tabs 14, 15, and 16, and shown in FIGS. 1, 2,and 4. The lower arm 21D of the photometric switch plate 21 is insertedand locked in the clearance between the lower locking tab 14 and themiddle locking tab 16. Each of the locking tabs 14, 15, and 16 isresilient, being unitarily formed with the plastic camera body.According to this embodiment, the locking tabs 14, 15, and 16 of theplastic camera body 13 slightly bend (resiliently) when the switchplates 21 and 22 are mounted to the body 13, but the plate spring switchplates 21 and 22 may be alternatively formed to be more resilient thanthe plastic camera body 13. When the photometric switch plate 21 isinserted, it pushes the locking-hook 14a of the resilient lower lockingtab downward, and also pushes the resilient middle locking tab 16slightly upward. The lower side of a camera body portion 13a provides anadditional resistance on the side of the lower locking tab 14 oppositethe middle locking tab 16. Alternatively, the locking tabs 14, 15, and16 can be formed to slightly overlap in the vertical direction to actagainst any moment upon insertion when the trailing edge of the lowerarm 21D passes the locking hook 14a, the lower arm 21D snaps into theclearance between the tabs 14 and 16, and the tabs 14 and 16 elasticallysnap back to their neutral positions. At this time, a click sound isgenerated, verifying the proper mounting of the photometric switch plate21. The locking hook 14a prevents any movement of the photometric switchplate 21 out of the clearance. Thus, the photometric switch plate 21inserted in the slit is locked into the clearance between the lowerlocking tab 14 and the middle locking tab 16 by the locking hook 14a.

The mounting base 22a of the release switch plate 22 is similarlysupported and locked, and is similarly inserted. Specifically, themounting base 22a of the release switch plate 22 is inserted and lockedin the clearance between the middle locking tab 16 and the upper lockingtab 15. When the release switch plate 22 is inserted, it pushes thelocking hook 16a of the resilient middle locking tab 16 downward, andalso pushes the resilient upper locking tab 15 slightly upward. Theupper side of the camera body portion 13a provides an additionalresistance on the side of the upper locking tab 15 opposite the middlelocking tab 16. When the trailing edge of the mounting base 22a passesthe locking hook 16a, the mounting base 22a elastically snaps into theclearance between the tabs 16 and 15, and the tabs 16 and 15 elasticallysnap back to their neutral positions. At this time, a click sound isgenerated, verifying the proper mounting of the release switch plate 22.The locking hook 16a prevents any movement of the release switch plate22 out of the clearance. Thus, the release switch plate 22 inserted inthe slit is locked into the clearance between the middle locking tab 16and the upper locking tab 15 by the locking hook 16a.

As shown in FIGS. 2 through 6, a shutter release button 17 and aself-timer button 18 are depressably supported on a front decorativeplate 10 (shown by a phantom line in FIGS. 5A, 5B, and 6). A commonswitch plate 19 constructed from electrically conductive plate springmaterial is fixed to the front decorative plate 10 near the shutterrelease button 17 and self-timer button 18. Specifically, the commonswitch plate 19 is fixed to the front decorative plate 10 by means ofpins 19d passing through a plurality of mounting holes 19a formed on thecommon switch plate 19 (as shown in FIGS. 4 through 6). The frontdecorative plate 10 is fixed in turn to the plastic camera body 13. Aresilient shutter release contact arm 19x and a resilient self-timercontact arm 19y fork from the (plate spring) common switch plate 19toward the lower portion of the shutter release button 17 and theself-timer button 18, respectively. The resilient contact arms 19x and19y are upwardly biased to contact the buttons 17 and 18, respectively,so that the shutter release button 17 and the self-timer button 18 areheld at their undepressed positions. The common switch plate 19 isfurther provided with a brush 19c to contact a common conductive plate12.

Since the photometric switch plate 22 is mounted in the camera body 13as shown in FIG. 2, when the front decorative plate 10 is assembled tothe camera body 13 to place the common switch plate in the positionshown in FIG. 3, the upper contact 21x opposes the shutter releasecontact arm 19x of the common switch plate 19. Furthermore, since therelease switch plate 22 is mounted in the camera body 3 as shown in FIG.2, the first contact 22x on the long arm 22L opposes the self-timercontact 19y of the common switch plate 19, and the second contact 22y onthe short arm opposes the bottom of the upper contact 21x of thephotometric switch plate 21. Thus, when the plates 19, 21, and 22 aremounted in the camera body 13 as shown in FIGS. 3 and 4, the secondcontact 22y, together with the shutter release contact 19x, acts as therelease switch RLS_(SW), and the upper contact 21x of the photometricswitch plate 21 is positioned between these two contact terminals.

A common conductive plate 12 having a first DX contact 12b is fixed onthe camera body 13, and a separate second DX contact 12a is fixed to thecamera body 13 near the first DX contact 12b. As shown in FIGS. 2 and 3,a film cartridge 11, to be placed in a cartridge chamber of the camerabody 13, is provided with a DX code conductive pattern 11d on the outersurface thereof.

DX code conductive patterns used on film cartridges have standardizedbinary code patterns of conductive portions and non-conductive portions,each distinctive DX code pattern representing a certain film speed.Within the many standard DX code patterns, some patterns are alike inone or more of the conductive or non-conductive portions of the pattern.More specifically, in some cases, similar film speeds are alike in atleast some portions of the identifying DX code pattern. For example, aspecific portion of the various DX code conductive patterns isnon-conductive for all standard film speeds under ISO 400, andconductive for all speeds including ISO 400 and above. In the context ofthis specification, a DX code pattern portion in a predeterminedposition that defines an exclusive set of film speeds, is defined as a"shared DX code portion". The film cartridge 11 shown in FIGS. 1 through3 is shown with a shared DX code portion 11e.

FIG. 7 shows a schematic including a controller 25, release switchRLS_(SW), photometric switch PH_(SW), the common conductive plate 12,the first and second DX contacts 12b and 12a, and a shared DX codeportion 11e. As shown in FIG. 7, inputs of the controller 25, connectedto the release switch RLS_(SW) and the photometric switch PH_(SW), aretied high. Furthermore, the DX contacts 12a, 12b, combined with theshared DX code portion 11e, act as a shared portion detection switchDX_(SW). An input of the controller 25, connected to the shared portiondetection switch DX_(SW), is tied high. As shown in FIGS. 1 through 4, aconnection to ground is provided for each of the switches RLS_(SW),PH_(SW), DX_(SW) by the common conductive plate 12. A portion (DXcontact 12b) of the shared portion detection switch DX_(SW) is unitarilyformed with the common conductive plate 12. The self-timer contact arm19y of the release switch RLS_(SW), and the shutter release contact arm19x of the photometric switch PH_(SW) are connected to the commonconductive plate 12 (as ground) by the brush 19c. The controller 25controls a metering sensor (not shown) and self-timer circuit shown)when one of the shown switches is turned ON or OFF.

As shown in FIGS. 1 through 3, when a film cartridge 11 is inserted inthe camera body 13, the DX contacts 12a and 12b contact the shared DXcode portion 11e of the DX code conductive pattern 11d of the filmcartridge 11. Thus, using the shared portion detection switch DX_(SW),the controller 25 detects which group of two exclusive film speed groups(for example, one of "below ISO 400" or "ISO 400and above") to which afilm inserted in the cartridge chamber belongs, according to the DX codeshared portion 11e. If no film is inserted, the controller 25 defaultsto one of the exclusive groups.

As shown in FIGS. 5A and 8, during a normal shutter release operation,when the shutter release button 17 is half depressed, the shutterrelease contact arm 19x of the common switch plate 19 moves down toelectrically contact the upper contact 21x of the photometric switchplate 21. As shown in FIG. 8, the controller 25 detects the closing ofthe photometric switch PH_(SW) (that is, a portion of the common switchplate 19 contacts the photometric switch plate 21), and a photometricmeasurement is taken in response. Then, when the shutter release button17 is further depressed, as shown in FIG. 5B, the shutter releasecontact arm 19x of the common switch plate 19, the upper contact 21x ofthe photometric switch plate 21, and the second contact 22y of therelease switch plate 22 all contact. As shown in FIG. 8, the controller25 detects the closing of both the photometric switch PH_(SW) and therelease switch RLS_(SW) (that is, portions of the common switch plate 19contact both of the photometric switch plate 21 and release switch 22),and the exposure operation is carried out in response.

As shown in FIGS. 6 and 9, when the self-timer button 18 is depressed,the self-timer contact arm 19y of the common switch plate 19 movesaccordingly down to electrically contact the first contact 22x of therelease switch plate 22. Consequently, the controller 25 detects thatthe release switch RLS_(SW) is closed (that is, that a portion of thecommon switch plate 19 contacts the shutter release plate 22), but thatthe photometric switch PH_(SW) is not, and a preset self-timer circuit(not shown) is operated in response. In this case, even though thephotometric switch PH_(SW) is not turned ON, the photometric measurementis instructed by the self-timer circuit just prior to the exposureoperation.

As described above, a self-timer operation is readily carried out, andthe switching device of the camera having a simple structure andimproved assembly efficiency is provided.

The present disclosure relates to subject matter contained in JapanesePatent Application No. HEI 06-326323, filed on Dec. 27, 1994, which isexpressly incorporated herein by reference in its entirety.

What is claimed is:
 1. A switching device for a camera, comprising:aphotometric switch; a release switch; a shutter release buttonoperatively connected to said release switch and to said photometricswitch for turning ON said photometric switch when said shutter releasebutton is half depressed and turning ON both of said release switch andsaid photometric switch when said shutter release button is furtherdepressed; and a self-timer button operatively connected to said releaseswitch, for turning ON only said release switch when depressed.
 2. Theswitching device according to claim 1, further comprising:control meansfor detecting said turning ON of said release switch and saidphotometric switch and for executing a self-timer operation when saidrelease switch is ON but said photometric switch is OFF.
 3. Theswitching device according to claim 2, wherein said control meansexecutes a photometric operation when said release switch is OFF butsaid photometric switch is ON, and executes a shutter release operationwhen said release switch is ON and said photometric switch is ON.
 4. Theswitching device according to claim 1, further comprising:a shutterrelease contact arranged to be depressable by said shutter releasebutton; a self-timer contact arranged to be depressable by saidself-timer button; a photometric contact opposing said shutter releasecontact provided to said photometric switch; and a first and a secondelectrical contact provided to said release switch, said firstelectrical contact opposing said self-timer contact, and said secondelectrical contact opposing said photometric contact.
 5. The switchingdevice according to claim 4,wherein when said shutter release button ishalf depressed, said shutter release contact electrically connects tosaid photometric contact, and when said shutter release button isfurther depressed, all of said shutter release contact, said photometriccontact, and said second electrical contact of said release switchelectrically connect, and wherein when said self-timer button isdepressed, said self-timer contact electrically connects to said firstelectrical contact of said release switch.
 6. The switching deviceaccording to claim 5, further comprising:control means for executing aself-timer operation, when said self-timer contact is electricallyconnected to said release switch, for executing a photometric operationwhen said shutter release contact is electrically connected to saidphotometric switch, and for executing a shutter release operation whenall of said shutter release contact, said photometric contact, and saidrelease switch electrically connect.
 7. The switching device accordingto claim 4,wherein said photometric switch comprises a photometricswitch plate upon which said photometric contact is provided, and saidrelease switch comprises a release switch plate upon which said firstand second electrical contacts are provided.
 8. The switching deviceaccording to claim 7,wherein said photometric switch plate and saidrelease switch plate are formed from conductive and resilient platespring material, and said photometric switch plate is formed in asubstantially U-shape, surrounding said release switch plate.
 9. Theswitching device according to claim 8,wherein said U-shape of saidphotometric switch plate includes an upper am above said release switchplate and a lower arm below said release switch plate, and saidphotometric contact is formed on said upper arm.
 10. The switchingdevice according to claim 7,wherein said self-timer contact and saidshutter release contact are provided on a unitary common switch plate,and wherein said photometric switch plate and said release switch plateare supported by a chassis of said camera, and said common switch plate,shutter release button, and self-timer button are supported by a frontdecorative plate fixed to said camera body.
 11. The switching deviceaccording to claim 10,wherein said common switch plate is provided witha plurality of arms including a first resilient arm bearing said shutterrelease contact and a second resilient arm bearing said self-timercontact, and said first resilient arm and said second resilient arm biassaid shutter release button and said self-timer button, respectively,toward depressed positions.
 12. The switching device according to claim10,wherein a plurality of resilient tabs, for holding said releaseswitch plate and said photometric switch plate, are provided on saidchassis displaced from one another, said plurality of resilient tabshaving clearances therebetween into which said release switch plate andsaid photometric switch plate are inserted.
 13. The switching deviceaccording to claim 12,wherein said plurality of resilient tabs comprisemeans for looking said release switch plate and said photometric switchplate into said clearances therebetween.
 14. The switching deviceaccording to claim 13,wherein said release switch plate is insertedlocked between a first and a second resilient tab of said plurality ofresilient tabs, and said photometric switch plate is inserted and lockedbetween said second resilient tab and a third resilient tab of saidplurality of resilient tabs.
 15. The switching device according to claim14,wherein said locking means comprises locking hooks provided to atleast each of said second and third resilient tabs.
 16. The switchingdevice according to claim 4,wherein said self-timer contact and saidshutter release contact are provided on a unitary common switch plate,and wherein said camera chassis is provided with an electricallyconductive plate for connecting said common switch plate with apredetermined shared code conductive portion of a film cartridgeinserted in the camera.